A study conducted at West Virginia’s largest medical center found that admissions for endocarditis related to drug abuse more than doubled between 2008 and 2015.

That parallels an increase in drug use in the state. Endocarditis is a life-threatening infection of the heart’s inner lining and valves.

One way you get it is through using dirty needles to shoot heroin or other injection drugs. In 2015, the researchers found that 66 people were admitted to the hospital for endocarditis related to drug abuse. That was up from 26 cases in 2008. Most often, the drug abuse was “mixed.”

That’s how the hospital codes opioids — which include prescription painkillers like Vicodin (hydrocodone) and OxyContin (oxycodone), as well as illegal drugs like heroin and illicitly made fentanyl.

Endocarditis is treated with intravenous antibiotics for two to six weeks, according to the National Institutes of Health. In some cases, surgery is also needed to repair damaged heart valves, or to help clear the infection.

According to the U.S. Centers for Disease Control and Prevention, nearly 64,000 Americans died of a drug overdose in 2016 — with opioids involved in two-thirds of those deaths.